全文获取类型
收费全文 | 2122篇 |
免费 | 67篇 |
出版年
2021年 | 29篇 |
2020年 | 20篇 |
2019年 | 32篇 |
2018年 | 49篇 |
2017年 | 44篇 |
2016年 | 61篇 |
2015年 | 31篇 |
2014年 | 51篇 |
2013年 | 243篇 |
2012年 | 77篇 |
2011年 | 106篇 |
2010年 | 48篇 |
2009年 | 45篇 |
2008年 | 68篇 |
2007年 | 82篇 |
2006年 | 50篇 |
2005年 | 65篇 |
2004年 | 84篇 |
2003年 | 61篇 |
2002年 | 54篇 |
2001年 | 43篇 |
2000年 | 33篇 |
1999年 | 34篇 |
1998年 | 33篇 |
1997年 | 24篇 |
1996年 | 25篇 |
1995年 | 28篇 |
1994年 | 28篇 |
1993年 | 23篇 |
1992年 | 33篇 |
1991年 | 20篇 |
1990年 | 28篇 |
1989年 | 19篇 |
1988年 | 29篇 |
1987年 | 20篇 |
1985年 | 18篇 |
1984年 | 22篇 |
1983年 | 33篇 |
1982年 | 15篇 |
1981年 | 26篇 |
1980年 | 26篇 |
1979年 | 27篇 |
1978年 | 20篇 |
1977年 | 20篇 |
1976年 | 22篇 |
1975年 | 20篇 |
1974年 | 28篇 |
1973年 | 23篇 |
1967年 | 14篇 |
1950年 | 14篇 |
排序方式: 共有2189条查询结果,搜索用时 15 毫秒
991.
992.
Ronald Eugene Stuart Noble 《Suicide & life-threatening behavior》1996,26(4):415-423
Suicide-related calls received by a crisis intervention center were analyzed for temporal variations. The overall number of calls, calls concerning personal suicidal ideation, and calls concerning third-person suicide potential varied by both month and day of the week. Ideation calls and calls involving a suicide attempt varied by day of the month. Month and day of the week variation in third-person calls paralleled variations in completed suicides. Fluctuations were large enough to be useful in scheduling crisis center staff. The possibility that third-person calls represent a greater suicide threat than first-person calls is discussed. 相似文献
993.
994.
995.
996.
997.
998.
999.
1000.
Dual task experiments have highlighted that driving while having a conversation on a cell phone can have negative impacts on driving (Strayer & Drews, 2007). It has also been noted that this negative impact is greater when reading a text-message (Lee, 2007). Commonly used in text-messaging are shortening devices collectively known as text-speak (e.g.,Ys I wll ttyl 2nite, Yes I will talk to you later tonight). To the authors' knowledge, there has been no investigation into the potential negative impacts of reading text-speak on concurrent performance on other tasks. Forty participants read a correctly spelled story and a story presented in text-speak while concurrently monitoring for a vibration around their waist. Slower reaction times and fewer correct vibration detections occurred while reading text-speak than while reading a correctly spelled story. The results suggest that reading text-speak imposes greater cognitive load than reading correctly spelled text. These findings suggest that the negative impact of text messaging on driving may be compounded by the messages being in text-speak, instead of orthographically correct text. 相似文献